1. Field of the Invention
This invention relates to a catalyst for the production of epoxides by catalytic vapor-phase oxidation of an unsaturated hydrocarbon having a carbon length of 4-20 carbon atoms and containing no allylic hydrogen atom with a molecular oxygen-containing gas thereby obtaining epoxides selectively in high yield.
2. Description of Related Art
Epoxide compounds are enable to use for extent. various reactions because of their high reactivity. For example 3,4-epoxy-1-butene which is one of epoxides of an unsaturated hydrocarbon having a carbon length of 4-20 carbon atoms and containing no allylic hydrogen atom, is an intermediate for the production of tetrahydrofuran (U.S. Pat. No. 5,034,545). Also the intermediate is used for a production of 1,2-butylene oxide (U.S. Pat. No. 5,034,545). It has been heretofore known that 3,4-epoxy-1-butene is produced by catalytic a vapor-phase oxidation of 1,3-butadiene with a molecular oxygen-containing gas in the presence of a catalyst. It has been also known that alumina, silicon and so on are used as the carrier thereof and an alkali metal and a thallium oxide are used as cationic components besides silver as catalyst component (WO89/07,101, WO93/03,024, U.S. Pat. No. 5,138,077, U.S. Pat. No. 5,081,096, and WO94/13,653).
These methods disclosed above, however, have the disadvantage that catalysts used therein possess low activity, exhibit low selectivity for 3,4-epoxy-1-butene, and suffer from a short catalyst life.
The catalysts for synthesizing epoxides include such catalysts as are obtained by depositing silver on porous inorganic carriers and used for the production of ethylene oxide. Among others there are silver-carried catalysts have been developed with a view to offering several years of service life on a commercial production. When these catalysts are used in the reaction for producing 3,4-epoxy-1-butene by the catalytic vapor-phase oxidation of 1,3-butadiene, they generally manifest substantially no catalytic activity or, if catalytically active at all, offer very short service lives as a catalyst. The epoxide of an unsaturated hydrocarbons having a chain length of 4-20 carbon atoms and containing no allylic hydrogen atom include such compounds as 3,4-epoxy-1-butene which need quantity production. For the catalysts to be effectively used in the reaction of a vapor-phase oxidation, it is an extremely important task for the sake of commercial production to enhance the performance of catalyst and elongate the service life of catalyst. Since the cause for degrading these catalysts remains yet to be elucidated, no effective method for solving this problem of degradation has been perfected so far.
An object of this invention, therefore, is to provide a novel catalyst for the production of epoxides by a vapor-phase oxidation of an unsaturated hydrocarbon having a carbon length of 4-20 carbon atoms and containing no allylic hydrogen atom.
Another object of this invention is to provide a method for manufacture of a catalyst for the production of epoxides having high activity, exhibiting high selectivity for epoxides, and enjoying a long catalyst life.
Further object of this invention is to provide a method of a catalyst for producing exoides.
Still another object of this invention is to provide a method for the production of 3,4-epoxy-1-butene in high yield by catalytic vapor-phase oxidation of 1,3-butadiene.
The objects mentioned above are accomplished by the following Items (1)-(4).
(1) A catalyst for the production of epoxides by a vapor-phase oxidation of an unsaturated hydrocarbon having a chain length of 4-20 carbon atoms and containing no allylic hydrogen atom, characterized by having a catalytic component containing silver and at least one element selected from the group consisting of alkali metals and thallium deposited onto a carrier obtained by mixing xcex1-alumina having a sodium content in the range of 1-70 mmol (as reduced to Na) per kg of xcex1-alumina with an aluminium compound, a silicon compound, and a sodium compound and calcining the resultant mixture, the carrier having a silicon content (as reduced to SiO2) in the range of 0.3-11.5 mass % based on the mass of the carrier and a sodium content (as reduced to Na2O) in the range of 0.11-2.5 mass % based on the mass of the carrier.
(2) A method for the preparation of a catalyst for the production of an epoxide by the vapor-phase oxidation of an unsaturated hydrocarbon having a chain length of 4-20 carbon atoms and containing no allylic hydrogen atom, characterized by causing a solution containing silver and at least one element selected from the group consisting of alkali metals and thallium to impregnate a carrier obtained by adding an aluminum compound, a silicon compound, and a sodium compound to xcex1-alumina having a sodium content (as reduced to Na) in the range of 1-70 mmols per kg of the xcex1-alumina and firing the resultant mixture and having a silicon content (as reduced to SiO2) in the range of 0.3-11.5 mass % per mass of the carrier and a sodium content (as reduced to Na2O) in the range of 0.11-2.5 mass % per mass of the carrier.
(3) A method for the production of epoxides, which comprises effecting said production by a vapor-phase oxidation of an unsaturated hydrocarbon having a chain length of 4-20 carbon atoms and containing no allylic hydrogen atom with a molecular oxygen-containing gas in the presence of a catalyst set forth in Item (1).
(4) A method for the production of 3,4-epoxy-1-butene, which comprising effecting said production by a vapor-phase oxidation of 1,3-butadiene with a molecular oxygen-containing gas in the presence of a catalyst set forth in Item (1).
The catalyst of this invention, owing to the construction thereof described above, excels in activity and selectivity for epoxide and enjoys a long life time. The use of this catalyst allows epoxide to be produced with high productivity by catalytic vapor-phase oxidation of unsaturated hydrocarbon. The above and other objects, features and advantages of the present invention will become clear from the following description of the preferred embodiments.